Artikel
Hamstrings vs BPTB: Their effectiveness in restoring gait patterns 2 years after ACL reconstruction
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Veröffentlicht: | 28. September 2006 |
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Gliederung
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Introduction: It has been found that the slight variations present between walking strides are not noise but actually have form. This structured stride-to-stride variability results from underlying mechanisms of the neuromusculoskeletal system and provides it with the flexibility to respond to unpredictable stimuli and stresses. Variability becomes impaired with aging, disease (i.e. Parkinson’s) or injury (i.e. ACL rupture). These findings are the result of using nonlinear tools to explore variability changes which are usually masked when traditional analysis (i.e. standard deviations) is adopted. In the present study we used the nonlinear tools of Approximate Entropy (ApEn) and Lyapunov Exponent (LyE) to identify changes in variations of the knee flexion-extension during walking in patients that were ACL reconstructed with bone-patellar tendon-bone (BPTB) and semitendinosus/gracilis (ST/G) autografts.
Methods: Seven patients with BPTB reconstruction (25.7 months after surgery), six patients with ST/G (25.5 months after surgery) and twelve controls walked on a treadmill at their self-selected pace. Two minutes (120 footfalls) of continuous data were recorded with a 6-camera optoelectronic (50Hz) system. We used ApEn to estimate regularity (low values signify increased regularity) and LyE to estimate sensitivity to initial conditions (low values signify decreased sensitivity) changes in the knee flexion-extension angular time series. Both groups of patients had similar IKDC, Tegner, and Lysholm scores. Therapeutic study, level of evidence: II (Prospective cohort study)
Results: For both parameters, the control had the smallest values, while the ST/G had the largest. Statistical analysis was performed using t-tests. Significant differences were found only between the control and the ST/G reconstructed knees for both parameters (p<0.05).
Conclusion: The ST/G reconstructed knee moves with a less regular and a less predictable pattern, and it is more sensitive to initial conditions than the control knee. However, the BPTB reconstructed knee seems to exhibit properties similar with the control. Further studies are required to firmly establish this result and identify the importance of using such variability tools to measure gait properties.